IJ4 ARTHUR G. VESTAL. 



Circotettix, M. fasciatus, and Camnula are not found outside of 

 the mountains, while Arphia, M. luridus, and M. minor are found 

 on the plains. Stenobothrus bears no particular relation to 

 climatic vegetation regions, as its presence is determined by 

 local conditions of moisture. 



The occurrence of Melanoplus angustipennis at Douglas Lake, 

 so far from the prairie region, seems at first very unusual. So 

 far as the writer is aware, the species is not recorded from Michi- 

 gan, though it must occur all along the Lake Michigan shore, and 

 is known from Ontario. Its most necessary environmental 

 condition is sandy soil, and this is well developed along most of 

 the shore-line of the Great Lakes. 



The five species of most wide distribution geographically are 

 those which have least definite habitat-preferences within a 

 particular area. The extensive range, and the fact that these 

 particular species are among those most important economically, 

 as destructive to crops, is to be explained in terms of tolerance 

 of widely varying conditions. 



The species which are restricted to forest habitats in the 

 Douglas Lake district are restricted geographically to forest 

 provinces. Certain of the species found in grassland or in open 

 forest in the region studied range outside the forest provinces, 

 being thus clearly independent of forest growth, while others 

 appear to be restricted to forested regions, though found in open 

 habitats. It is probable that Camnula pellucida and Circotettix 

 verruculatus are restricted to the mountain areas of Colorado 

 by radical changes in physical conditions from mountains to 

 plains, rather than by changes in vegetation. 



In general, it may be said that grasshopper species associated 

 with the climatic plant association have the same geographic 

 range as this association. This range, when shared by many 

 species, determines the ecological province. Where two similar 

 climatic vegetation regions adjoin, as in the case of northeastern 

 and northwestern conifer regions, the same grasshopper species 

 may range over both, in similar associations. Certain species 

 may also range locally into other provinces, in habitats locally 

 approximating those of their own climatic association. Species 

 associated with local habitats may be restricted to the province, 



